Ellen hirst adminis



(No Model.)

R. B. HIE ST, Decd.

E. Hmsr, Administratrix. STARTING BOX FOR ELECTRIC MOTORS.

No. 589,433. Patented Sept. 7,1897. FIG. I.

FIG. 3.

WITNESSES: INVENTOR: Z T {M I By his Azzorneys.

W@.@rnw g UNITED STATES PATENT OFFICE.

ROBERT I IIIRST, OF BROOKLYN, NEW YORK; ELLEN IIIRST ADMINIS- TRATRIX OFSAID ROBERT I). IIIRST, DECEASED.

STARTING-BOX FOR ELECTRIC MOTORS.

SPECIFICATION forming part of Letters Patent No. 589,433, datedSeptember '7, 1897. Application filed July 3, 1897. Serial No. 643,470.(No 1110(l6l.l

To all whom it may concern:

Beit known that I, ROBERT B. IIIRs'r, a citizen of the United States,residin gin Brooklyn, in the county of Kings and State of New York, haveinvented certain new and useful Improvements in Starting-Boxes forElectromotors, of which the following is a specification.

This invention provides an improved starting-box for electromotorsdesigned to avoid the necessity of providing an external switch forbreaking the main circuit in order to stop the motor.

My improved starting box enables both the starting and stopping of themotor to be e1":- fected by the manipulation of the same handle orlever.

My invention is also applicable to controllers for electromotors.

I employ any ordinary resistance-box having a controlling handle orlever serving as the switch-arm for making connection with one or otherof the resistance-contacts. I provide said boX with a double-poleswitch,

the fixed leaves or members of which are connected to the circuit-mains,while the movable leaves or members are connected to move together, areprovided with a spring for drawing them to the open position, and arearranged to be displaced by the resistanceboX lever to bring them to theclosed position in the act of starting the motor. I provide the usualretaining-magnet or shuntmagnet for holding said switch closed, and inthe shunt-circuit of said magnet I provide any usual overload-magnetadapted when eX- cited beyond the normal by an excessive current toattract its armature and thereby break said shunt-circuit, so as to openthe switch, break the main circuit, and stop the motor. In addition Iprovide any suitable means operated by said lever for breaking thecircuit of said retaining-magnet in order to enable the operator to stopthe motor at will.

Figure 1 of the accompanying drawings is an. elevation or face view ofmy improved starting-box, the circuit connections being shown indiagram. Fig. 2- 'is a sectional elevation of the overload-magnet. Fig.3 is an elevation showing a modified arrangement.

Fig. a is a face view showing a modification of Fig. 1.

Let A designate a resistance-box of any suitable construction havingcontacts a a and resistances or coils between them (inclicateddiagrammatically at b b.) The usual lever B is arranged to move over thecontacts in order to throw more or less resistance into circuit.

M designates the motor to be controlled, its armature being connected ina circuit 0 and its field-magnet coils in a circuit (1. Convenientlyarranged on the resistance-box is a double-pole switch O O of any usualor suitable construction for closing or breaking the main circuit. I11the construction shown this is a knife-switch, the arms O and O beingpivoted at e and 6, respectively, and connected by an insulating-bar f,constituting a parallel-motion device for forcing the two arms to movetogether. When in the position shown in full lines, the switch-armsenter between the leaves of the fixed members g g, which connect withbinding-posts 71 7t, to which the circuit-mains are joined.

The switch O O carries an armature 1 which when the switch is in theclosed position comes into contact with a retaining-magnet D, theattraction of which holds the switch closed against the tension of aspring E, which strives constantly to open it. This spring E may bearranged in any suitable way, preferably by coiling it around one of theposts 6 e, but for clearness I have shown it as a tensile helicalspring.

The magnet D is a shunt-magnet connected between the pivotal posts 6 eby means of a shunt circuit orloop 10 10. (Shown in dotted lines.) Thisshun t-circuit is controlled by an overload1nagnetF of any ordinaryconstruction, being usually a series magnet connected in the maincircuit and acting as a relay which normally holds the shunt 1O closed,but upon the passage of an abnormal current its armature is attractedand breaks the shunt. In the construction shown its armature j has aretracting-sprin g 7.2, which presses it strongly against a fixed butadjustable contact-screw t.

The circuit connections extend from binding-post 7L through switchmembers g and G to post c. Here the circuit divides, one branch passingthrough the field magnet coils of the motor and the other branch passingthrough the resistance-box to the armature. The field connection is bywire ll to binding-post 12, thence by wire cZ through the field tobinding-post 13 and by wire 14: to post 0 and by switch members 0 and gto the opposite binding-post h. The armature connection is from post 0by wire 15 to the pivot of lever 13, thence through this lever to anycontact a, on which it may rest, and through any of the interveningresistance-coils Z) Z) to the final contact a, thence through the coilof overload-magnet F and by wire 10 to binding-post 1'7, and thence bywire 0 through the armature to binding-post l3, and out as before.

The lever B is arranged in any relation with the switch 0 C, by whichthe movement of the lever to cut in all the resistance is made effectiveto throw the switch to the closed circuit position, thereby starting themotor. I may arrange the parallel barf or any other part of the switchin the path of the lever, but preferably I have provided a pin orprojection m, which projects into the path of the lever.

\Vhen the motor is at rest, the switch is in the position shown indotted lines, and the lever may be preferably in mid-position. To startthe motor, the lever is thrown over to the position shown in full lines,and in so doing it strikes the pin on and throws the switch over to itsclosed position, while at the same time the lever cuts in all theresistance of the box in circuit with the armature. The motor thenstarts, and as it gains speed the operator gradually cuts out resistanceby moving the lever B in the contrary direction, until finally at fullspeed it stands upon the terminal contact a. The switch is not drawnback by the tension of its spring E, but is held by the attraction ofthe shuntmagnet D. The motor will now run continuously until stopped inone or other of three ways, either, first, by the occurrence of anoverload, or, second, by a cessation of current 011 the main circuit,or, third, by the act of the operator when he desires to stop it. In thefirst case the magnet F becomes overexeited and attracts its armatrn-e,thereby breaking the shunt-circuit 10 at Z, so that magnet D isdemagnetized and lets go the switch, which is instantly thrown over bythe spring E to the open position shown in dotted lines, therebybreakingthe circuit and stopping the motor. In the second case the magnet I) isdemagnetized by the drop in voltage. In the third case the shunt-circuit10 is broken by a movement imparted to the lever B in the manner which Iwill now describe.

I provide any suitable means to be operated by a movement of the leverfor breaking the circuit of the retaining-magnet. The preferred means isthat best shown in Fig. 2, by which the lever 1 acts mechanicallyuponthe armature of the magnet F to pull it away from the screw Z, to thesame effect as though the magnet F were overcharged. Connected to thearmature is an arm or slide 2), having a hooked end p, with which endcooperates a stiff spring q, carried by the lever B. By moving the lever13 to the position of full speed (shown in dotted lines in Fig.1 and infull lines in Fig. 2) the spring (1 moves over the beveled end 1) andsnaps past it to the position shown in Fig. 2. In so doing its thrustexerted against the slidep presses it into firmer contact with the screwZ. \Vhen the operator desires to stop the motor, he moves the lever B inthe contrary direction, whereupon its springarm q catches against theabrupt end of the hook p and displaces the slide 1), pulling it out ofcontact with the screw Z, and thereby breaking the shunt-circuit 10,with the effect of demagnetizing the retaining-magnet, releasing theswitch, and stopping the motor. To the same effect I may introduce aseparate circuit-breaker, as shown in Fig. 3, where a leaf-sprin g gpresses against a stop-screw Z, both being in the circuit 10 andconstituting a circuit-breaker. The spring q projects up into the pathof the spring-arm (1 of the lever 13, which, moving toward the positionshown in dotted lines, snaps past the spring q without impairing itscontact with the screw Z, but on the return movement the spring-arm qpresses the spring q away from the screw and breaks the circuit. Homewith either of these construc tions the operator in order to stop themotor has only after having carried the lever to its extreme position todisplace it slightly in the contrary direction. Ile should not move itfar enough to displace the switch from its open position.

In case it is desired to control the speed of the motor by introducingmore or less resistance for the purpose of varying the current whichtraverses its armature the mechanical circuit-breaker, which is operatedby the lever B, has only to be placed in an intermediate positioninstead of at the extreme position, as shown, for example, in Fig. 4:.In this figure the construction is the same as already described, exceptthat the overloadmagnet F,with the mechanical circuit-breaker shown inFig. 2, is arranged, for example, midway of the row ofresistance-contacts a a, the contact a in this case not being the finalcontact, but one of a series of contacts a a a, &c., whereby theresistance is varied according to the manner of controllers for electromotors.

My invention enables the motor to be both started and stopped bymanipulating the lever of the starting-box and avoids the necessity ofthe outside double-pole switch heretofore required.

My invention is not limited to the exact arrangement of parts shown andheroin described, it being understood that the switch may be differentlyarranged with relation to IIC the lever and that any suitable mechanicalconstruction or connection may be adopted for causing the movement ofthe lever to the starting position to displace the switch to the closedposition. This may be accomplished either directly, as shown, or by someindirect mechanical connection. Neither is my invention limited to theexact details of construction of the switch or other elements of thedevice, as my invention is applicable with other constructions ofswitches, and in other respects is open to considerable modification inmechanical or structural details so long as the essential features of myinvention are not departed from.

I claim as my invention 1. The combination with a resistance-box and itslever of a switch controlling the main circuit, movable to closedposition by said lever, a spring tending to open said switch, aretaining-magnet adapted when excited to hold said switch closed, andmeans operated by said lever forbreaking the circuit of said magnet torelease said switch.

2. The combination with a resistance-box and its lever of a switchcontrolling the main circuit, movable to closed position by said lever,a spring tending to open said switch, a retaining-magnet adapted whenexcited to hold said switch closed, an overload-magnet adapted whenexcited beyond the normal to break the circuit of said retaining-magnet,and means operated by said lever for breaking said circuit to releasesaid switch.

The combination with a resistance-box and its lever of a switchcontrolling the main circuit, movable to closed position by said lever,a spring tending to open said switch,

a retaininganagnet adapted when excited to hold said switch closed, anoverload-magnet adapted when excited beyond the normal to attract itsarmature to break the circuit of said retaining-magnet, and a mechanicalconnection between said overload-magnet and said lever, whereby themovement of said lever acts upon said armature to break the circuit ofsaid retaining-magnet.

4. The combination with a resistance-box and its lever, of a double-poleswitch controlling the connection of the respective circuitmains, withthe resistances and motor movable to closed position by said lever, aspring tending to open said switch, a retaining-magnet adapted whenexcited to hold said switch closed, and means for breaking the circuitof said magnet to release said switch whereby the motor is controlledsolely by the resistance-box switch.

5. The combination with a resistance-box and its lever, of a double-poleswitch controlling the circuit-mains, constructed with movable arms ormembers C C turning around separate pivot-posts c c, with an insulatingparallel barf connecting them, an armature carried by said bar, aretaining-magnet arranged to attract said armature, a spring forthrowing said switch open, and means for breaking the circuit of saidmagnet to release said switch.

In witness whereof I have hereunto signed my name in the presence of twosubscribing witnesses.

ROBERT B. IIIRST. lVitnesses:

ARTHUR O. FRASER, FRED WHITE.

